Electrocatalysis最新文献

Among naturally occurring polymers, lignin is the most abundant source of aromatic compounds. Electrocatalytic valorization of lignin derivatives into value-added chemicals represents a sustainable and promising strategy, leveraging the increasing accessibility of intermittent renewable electricity and abundant biomass feedstocks. Compared to the thermal catalytic conversion, electrocatalytic hydrogenation (ECH) and hydrodeoxygenation (HDO) are emerging as key technologies for biomass conversion, owing to their ability to utilize renewable electricity for in situ generation of environmentally benign H₂ and other essential reagents. Recent progress in ECH and hydrogenolysis of lignin-derived oxygenated aromatic compounds has demonstrated viable pathways for synthesizing industrially critical chemicals, offering a potential alternative to fossil resource dependency. Nevertheless, research on catalyst design, reaction mechanisms, and system optimization for the electrocatalytic upgrading of lignin derivatives remains in its early stages, necessitating further fundamental and applied investigations. This review begins by providing a comprehensive overview of electrocatalytic hydrogenation and hydrogenolysis processes applied to lignin-derived substrates. Finally, challenges facing and future opportunities for electrocatalytic lignin valorization pathways are discussed.

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In this paper, Ni@Co₃O₄-s-rGO was synthesized and constructed as a non-enzymatic sensor to detect hydrogen peroxide (H₂O₂). The prepared sample was characterized using SEM–EDX, UV–vis, XRD, and Raman spectroscopy. In 0.1 M phosphate-buffered saline (PBS), the fabricated Ni@Co₃O₄-s-rGO amperometric sensor demonstrated a high sensitivity of 160.3 µA·mM⁻¹ towards H₂O₂ within the linear detection range of 1 to 2000 µM. The detection limit was also determined as 3.6 µM. Furthermore, the Ni@Co₃O₄-s-rGO catalyst demonstrated high selectivity towards H₂O₂, even in the presence of common interferents. The enhanced electrochemical sensing ability of the catalyst is attributed to the synergy of three factors: the relatively large electrode active area, the high electrical conductivity, and the electron mobility in the presence of ultra-nanosized Ni particles.

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Hydrogen production via water electrolysis has garnered significant attention as a pivotal technology for green energy conversion. In this work, cheap metal ions copper and iron are used as catalyst raw materials to develop high efficiency and low cost HER catalyst. Copper-doped iron phosphide supported on carbon paper (Cu-FeP/CP) is synthesized via a simple two-step process involving hydrothermal growth followed by high-temperature phosphidation. The morphology and electrochemical performance of iron phosphide catalysts with controlled copper doping are investigated. A nano-needle-like Cu-FeP/CP structure with 3% Cu doping exhibits a high surface area, providing abundant active sites, while Cu-induced charge redistribution and Fe-Cu synergy further enhance its intrinsic catalytic activity. HER catalytic performances results reveal Cu-FeP/CP-3% electrode exhibits low overpotentials of 71 mV in 0.5 M H₂SO₄ and 123 mV in 1 M KOH to achieve a current density of 10 mA cm⁻², along with small Tafel slopes of 49 mV dec⁻¹ and 72 mV dec⁻¹, respectively. Additionally, Cu-FeP/CP-3% shows low charge transfer resistance and stable HER performance over 24 h. The result provides new insights into the design and fabrication of highly efficient and cost-effective HER catalysts.

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Over the years, there has been a surge in the quest for the replacement of noble metal-based electrocatalysts for the efficient oxygen evolution reaction (OER) in an alkaline medium. Herein, a facile synthesis of NiO/delaminated boron composite and its electrocatalytic activity is reported. The influence of the loading level of delaminated boron on the electrocatalytic OER activity of NiO in 1 M KOH medium is investigated systematically. The linear voltammetry study reveals that all NiO/delaminated boron (NiO-B-_X) composites demonstrate a higher current density response as well as lower overpotential compared to NiO. The presence of the borophene in the composite could have resulted in the introduction of positive charge carriers on NiO, thereby improving the kinetics of the OER. Besides, the dispersion of the NiO particles onto the surface of delaminated boron is expected to mitigate the aggregation of NiO particles and expose a larger number of electrochemically active sites, consequently enhancing the overall OER performance. Evidently, NiO-B-_X electrocatalysts prepared with 10 mg of the borophene, (NiO-B-₁₀), demonstrate both the lowest overpotential at 10 mA cm⁻² of 1.61 V and Tafel slope of 61.25 mV dec⁻¹. It also exhibits extended stability over 8 h.

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A highly sensitive MWCNTs paste electrode (MWCNTPE) modified with chitosan-nickel complex (Chit-Ni²⁺) was designed for the efficient electrochemical determination of uric acid (UA). The MWCNTPE surface is drop-coated with the Chit-Ni²⁺ complex. The electroanalytical performance of Chit-Ni²⁺ complex modified MWCNTPE toward UA is thoroughly analyzed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Experimental results reveal that Chit-Ni²⁺ complex modified MWCNTPE exhibits superior electrochemical performance toward determination of UA as compared to bare MWCNTPE. The voltammetric sensitivity of Chit-Ni²⁺ complex modified MWCNTPE toward UA oxidation was significantly improved, with a typical peak potential of 0.39 V (vs. SCE) in LiCl solution (0.1 M) at pH 2.4. Chit-Ni²⁺ complex modified MWCNTPE exhibited a linear current response (R² ~ 0.999) in the range of 0.05–144.3 µM UA. The limit of detection (LOD) limit for the Chit-Ni²⁺ complex modified MWCNTPE is found to be 0.01 µM. The Chit-Ni²⁺ complex modified MWCNTPE was highly selective for the electrochemical determination of UA even in the presence of other potential biomolecular interfering species.

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Given the economic, industrial, and environmental value of green dihydrogen (H₂), optimization of water electrolysis as a means of producing H₂ is essential. Binders are a crucial component of electrocatalysts, yet they remain largely underdeveloped, with a significant lack of standardization in the field. Therefore, targeted research into the development of alternative binder systems is essential for advancing performance and consistency. Binders essentially act as the key to regulating the electrode (support)–catalyst–electrolyte interfacial junctions and contribute to the overall reactivity of the electrocatalyst assembly. Therefore, alternative binders were explored with a focus on cost efficiency and environmental compatibility, striving to achieve desirable activity and stability. Herein, the alkaline hydrogen evolution reaction (HER) was investigated, and the sluggish water dissociation step was targeted. Controlled hydrophilic poly(vinyl alcohol)-based hydrogel binders were designed for this application. Three hydrogel binders were evaluated without incorporated electrocatalysts, namely PVA₁₄₅, PVA₁₄₅-blend-bPEI_1.8, and PVA₁₄₅-blend-PPy. Interestingly, the study revealed that the hydrophilicity of the binders exhibited an enhancing effect on the observed activity, resulting in improved performance compared to the commercial binder, Nafion™. Notably, the PVA₁₄₅ system stands out, with an overpotential of 224 mV at − 10 mA·cm⁻² (geometric) in 1.0 M KOH, compared to the 238 mV exhibited by Nafion™. Inclusion of Pt as active material in PVA₁₄₅ as binder exhibited a synergistic increase in performance, achieving a mass activity of 1.174 A.cm⁻².mg⁻¹_Pt in comparison to Nafion™’s 0.344 A.cm⁻².mg⁻¹_Pt, measured at − 150 mV vs RHE. Our research aimed to contribute to the development of cost-effective and efficient binder systems, stressing the necessity to challenge the dominance of the commercially available binders.

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Utilization of PVA-based polymers as alternative binders to enhance the sustainability and efficiency of the alkaline HER

The eco-friendly electrocatalytic nitrate reduction reaction (NO₃RR) at ambient condition is in high demand as a potential replacement for the Haber–Bosch process and for efficient wastewater treatment. The two multicomponent alloys electrocatalysts based on non-noble metals of Co75Si15Fe10 and Co75Si15Fe5Cr5 were synthesized. The samples were characterized and studied by the SEM, EDX, XRD, UV–vis spectroscopy, linear voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Under the conditions of chronoamperometry, ammonia was synthesized by NO₃RR and the values of Faradaic efficiency (FE) and yield rate of NH₃ were obtained. The highest FE 58.7% and the largest yield rate of NH₃ 4.3 μmol h⁻¹ cm⁻² at potential − 0.585 V (RHE) in a neutral electrolyte for the Co75Si15Fe10 electrocatalyst for NO₃RR. Unexpected for this work was the discovery of an inhibitory effect for an alloy containing a small amount of Cr. This work opens up interesting opportunities for further research of multicomponent alloys for NO₃RR.

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The multicomponent alloys electrocatalysts of Co75Si15Fe10 and Co75Si15Fe5Cr5 were synthesized. The eco-friendly electrocatalytic nitrate reduction reaction at ambient condition was used. Ammonia was synthesized by NO₃RR and the yield rate of NH₃ = 4.3 μmol h⁻¹ cm⁻². The Faradaic efficiency, FE = 58.7% at potential, E =  − 0.585 V (RHE).

In the present work, a straightforward approach was adopted to synthesize concentration-dependent multiwall carbon nanotubes with silver-doped titanium oxide (Ag-TiO₂) composites. The antibacterial activity was examined against Gram-positive and Gram-negative bacteria, increasing from 12.5 to 16.5 mm for S. aureus, 20.5 to 26 mm for C. jejuni, and 19.5 to 25.5 mm for V. cholerae, incorporating 5% and 10% MWCNTs with Ag-TiO₂, respectively. An Ag-TiO₂-10% MWCNTs-GCE system was developed for the simultaneous detection of ascorbic acid (AA) and paracetamol (PA). Under optimal conditions, the sensor demonstrates linearity for AA (0.5–300 µM) and PA (0.01–500 µM) (n = 3), respectively. The corresponding detection limits for AA and PA were 0.038 and 0.008 μM. This electrochemical sensor exhibits tremendous promise for a variety of medical applications, particularly in AA and PA monitoring, and offers a straightforward and extremely sensitive approach for detecting AA and PA in human serum samples and pharmaceutical samples.

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Electrochemical sensing is a promising approach for the selective and highly sensitive sensing of oxidized and reduced states of Nicotinamide adenine dinucleotide (NAD⁺/NADH). However, the limited selectivity, large overpotential requirements and the electrode fouling concerns associated with the till date reported NADH-specific electrodes continue to impede their potential utility for the design and development of fast, inexpensive and highly reliable point of care devices for electrochemical sensing of NAD⁺ and NADH. Herein we present a simple covalent functionalization approach for the design and development of Cytochrome-c (Cyt-c) functionalized Cu-BDC MOF (Cyt-c/Cu-BDC) as a novel Cu-Fe based bio-mimic for electrochemical sensing of NADH. Our detailed physical, chemical and electrochemical investigations carried out over the so designed Cyt-c/Cu-BDC composite establish it as an electronically conducting, electrochemically stable redox-active electrode material with an exceptional activity towards the selective and ultrasensitive electrochemical sensing of NADH. We demonstrate the practical utility of Cyt-c/Cu-BDC composite for accurate and sensitive electrochemical sensing of NADH in the pico-molar concentration range. The herein demonstrated extremely low LOD (10.4 pM), high sensitivity (12.02 ± 0.119 μA nM⁻¹ cm⁻²), good anti-interference ability and prolonged stability of the Cyt-c/Cu-BDC composite is far superior than the till date reported electrochemical sensors for NADH. These features qualify Cyt-c/Cu-BDC composite as a promising electrode material for the design of point-of-care NADH sensing devices for clinical diagnostics.

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Herein, we present a selective and sensitive electrochemical sensor for detecting formaldehyde in cosmetics, based on cobalt ferrite nanoparticles (CoFe₂O₄ NPs) modified on a glassy carbon electrode (GCE). The CoFe₂O₄ NPs were synthesized using a green biosynthetic route and characterized using UV–Visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The electrochemical performance of the GCE-CoFe₂O₄ NPs sensor was evaluated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and chronoamperometry (CA). Compared with the bare GCE, the modified electrode exhibited a significantly greater oxidation peak current for formaldehyde. The sensor demonstrated a linear dynamic range with a regression coefficient (R²) of 0.9193 and achieved limits of detection (LoD) and quantification (LoQ) of 0.056 mM and 0.184 mM, respectively, using DPV. Selectivity tests confirmed minimal interference from common substances such as ethanol and acetone at 10 mM concentrations. The sensor also exhibited excellent repeatability and reproducibility, with relative standard deviation (RSD) values of less than 5%. Practical applications of the sensor in detecting formaldehyde in nail polish remover yielded recovery rates ranging from 94 to 113%, demonstrating its reliability for real-world use. This study highlights the potential of green-synthesized CoFe₂O₄ NPs in the development of sustainable and efficient electrochemical sensors for monitoring harmful substances in consumer products.

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